Research And Implementation Of Embedded Variable Frequency Speed Control System Based On CAN Bus

With the development of power electronics technology, microprocessor control technology, field bus control technology and motor control technology, the performance of AC motor speed control is getting better. AC motor control system currently has the trend to replace DC speed control systems. There are higher requirements of the performance of AC motor control with the development of national economy and science technology, including higher speed accuracy, faster response and so on. The vector control technique can achieve decoupling control of flux and torque by decomposing the stator current of asynchronous motor and controlling, so that we can control asynchronous motor like DC motor and achieve its control effect. Based on these advantages, vector control technology is widely used in AC speed control systems.Adapted genetic algorithm is suitable for solving complex, nonlinear problems, this is full compliance with multi parameters, nonlinear characteristics of AC motor, so that it can be used for optimizing of the parameters of asynchronous motor controller. The parameters that optimized by adapted genetic algorithm can get even better result than the parameters obtained by experience.This paper selects Research and Implementation of Embedded Variable Frequency Speed Control System Based on CAN Bus as a research topic, proposes a method for parameter optimization of speed controller based on adapted genetic algorithm, and compare and analysis the result that using the parameters obtained by experience; Because S3C44B0 doesn't have CAN bus interface itself, we propose a method for expansion CAN bus interface; TransplantμC/OS-Ⅱreal time operate system on S3C44B0; Finally, using VC++6.0 write serial application programs, and design of the monitor software system of asynchronous motor. The contributions of this dissertation can be summarized as follows:(1)The research of parameters optimization of asynchronous motor speed controller base on adapted genetic algorithmTo make the system response time less, minimize errors, we chose PI controller, combine with the multi variables and nonlinear characteristics of asynchronous motor, using adapted genetic algorithm to optimize the PI parameters; To illustrate the advantages of using this method, this article has simulates by MATLAB using the parameters obtained by experience of speed controller, and the result show that the velocity curve is very good, that no overshoot, fast response, by using the parameters optimized by adapted genetic algorithm.(2)The software and hardware design for asynchronous motor speed control system based on S3C44B0In the asynchronous motor speed control system involves to the current, speed examination circuit, power transfer circuit and so on, these circuits are very important for the whole system. The software design is based on the hardware design, including the variables coding, initializing the I/O port, setting the value of the control bits that involving to the vector control. Finally, we implement the joint testing of software and hardware to make it can achieve our desired results.(3)Expansion CAN interface to S3C44bO and transplantμC/OS-Ⅱto itThis paper uses CAN bus to communicate with the superior computer, to use this stable field bus proposes a method to expansion for S3C44B0 because it does not have CAN bus interface itself. TransplantμC/OS-Ⅱreal time operate system kernel on S3C44B0; Design a monitor system of asynchronous motor by using VC++6.0 write serial communication. This monitor system, which has the advantage of easy operating for the people who control it, can be controlled by the person authorized and shows real-time speed curve, it is suitable for field operation staff.